The increasing worldwide prevalence of carbohydrate-related metabolic diseases including diabetes, obesity, metabolic syndrome, and their related long-term consequences, continues to pose a challenge to health care systems (1). Poor and unbalanced diet is considered a major environmental insult contributing to the increase in metabolic disease incidence, especially in younger individuals.
Animal models exist that mimic most features of human diabetes. Such models are useful for better understanding the connection between diet and disease, and for developing dietary guidelines and improving management of the disease (2). The male Nile rat is an effective model for the study of type-2 diabetes mellitus and metabolic syndrome due to the animal's natural genetic susceptibility to these diseases and to alteration of the progression and outcome of these diseases by diet. The pathogenesis, as well as the animal's response to nutritional manipulation, conforms to the human disease (3-6). Studies with the Nile rat have demonstrated that neutralizing the glycemic load of a standard high carbohydrate diet by adding acarbose (a drug used to treat type-2 diabetes) or enhancing insulin sensitivity by supplementing metformin (another drug for type-2 diabetes) exerted significant anti-diabetic effects, demonstrating the similarities between NR and human metabolism (K. C. Hayes, unpublished results, 2014). Even as new classes of oral anti-diabetic drugs are being developed and designed (7), establishing a diet-based approach to delay or completely prevent the need for such anti-diabetic medication would be a useful adjunct for individuals suffering from type-2 diabetes mellitus or impaired glucose tolerance.
Reducing the glycemic index and/or glycemic load may reduce the risk for type-2 diabetes in humans (8-10). A recent meta-analysis of 14 studies suggests that glycemic index and glycemic load of foods are meaningful predictors of type-2 diabetes risk in younger subjects if the diet glycemic load data are updated periodically (10). This concept reportedly works as well for cardiovascular risk (11). Dietary fiber has generally proven beneficial in clinical trials focused on fruit and legume intake that improved blood glucose levels and other metabolic parameters (12-16).
Biyani et al. in U.S. Pat. No. 6,361,818 describe a low fat, high fiber carrot product containing 20-50% by weight dietary fiber in which insoluble fiber substantially exceeds soluble fiber. The product is made by combining carrot juice from crushed carrots with a variety of ingredients, concentrating the mixture, adding the concentrate to a carrot pomace, and drying the mixture under vacuum. The resulting high fiber granules are also high in sugars from the added juice. Ingestion of the granules increases satiety, decreases food consumption, and promotes weight loss.
Didden in U.S. Patent Appl. No. 2014/0127297 describes a nutraceutical composition for limiting the absorption of dietary lipids for inducing weight loss. The composition contains a high fiber carrot extract combined with insoluble fiber from apple and/or oat. The resulting compositions when orally administrated decrease absorption of dietary lipids and promote weight loss in mammals including humans.
There remains a need for nutritional compositions and methods for treating and/or preventing type-2 diabetes and its progression.